always use max cmake when cmake3 and cmake are all existed (#69355)
Summary:
For Pytorch source build when using Ninja generator, it requires **CMake >=3.13**, Pytorch always checks **cmake3 >= 3.10** first, so when **3.13> cmake3 >= 3.10** and then PyTorch will use cmake3, there will report an error: ```Using the Ninja generator requires CMake version 3.13 or greater``` even the **CMake >=3.13** .
For example: for my centos machine, the system CMake3 is ```3.12```, and my conda env's CMake is ```3.19.6```, there will have a build error which PyTorch choose CMake 3, I can update CMake3 or create an alias or a symlink to solve this problem, but the more reasonable way is that ```_get_cmake_command ``` always return the newest CMake executable (unless explicitly overridden with a same CMAKE_PATH environment variable).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69355
Reviewed By: jbschlosser
Differential Revision: D33062274
Pulled By: malfet
fbshipit-source-id: c6c77ce1374e6090a498be227032af1e1a82d418
